The benzimidazole nucleus forms the basis of a number of useful materials, including polymeric structural materials (fibers) and biologically active compounds. Thus, ways of elaborating the molecular structure, particularly the 2-position, are needed in many applications.
In theory, Reissert compounds derived from benzimidazole offer the opportunity for such chemical manipulations (see Advances in Heterocyclic Chemistry, 1979, 24 187-214 for a review). Although analogs derived from chloroformates have been reported (see J. Heterocyclic Chem., 1987, 24, 1349-1351), all attempts to produce the more synthetically useful Reissert compounds by reaction of benzimidazole with acid chlorides in the presence of a cyanide source led to destruction of the benzimidazole ring system (see J. Chem. Soc., Chem. Comm., 1984, 1245-1246).
The instant invention is a method for the synthesis of Reissert compounds from benzimidazole by a two-step procedure.